syzbot


KCSAN: data-race in mprotect_fixup / try_to_migrate_one

Status: upstream: reported on 2025/02/05 11:41
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+c2e5712cbb14c95d4847@syzkaller.appspotmail.com
First crash: 21h29m, last: 21h29m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] KCSAN: data-race in mprotect_fixup / try_to_migrate_one 11 (12) 2025/02/05 16:25

Sample crash report:
==================================================================
BUG: KCSAN: data-race in mprotect_fixup / try_to_migrate_one

write to 0xffff888114b41700 of 8 bytes by task 6432 on cpu 1:
 vm_flags_init include/linux/mm.h:875 [inline]
 vm_flags_reset include/linux/mm.h:887 [inline]
 mprotect_fixup+0x419/0x5e0 mm/mprotect.c:679
 do_mprotect_pkey+0x6cc/0x9a0 mm/mprotect.c:840
 __do_sys_mprotect mm/mprotect.c:861 [inline]
 __se_sys_mprotect mm/mprotect.c:858 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:858
 x64_sys_call+0x2770/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888114b41700 of 8 bytes by task 6418 on cpu 0:
 try_to_migrate_one+0xb5a/0x12e0 mm/rmap.c:2321
 rmap_walk_anon+0x28f/0x440 mm/rmap.c:2646
 try_to_migrate+0x11f/0x150
 migrate_folio_unmap mm/migrate.c:1320 [inline]
 migrate_pages_batch+0x786/0x1930 mm/migrate.c:1866
 migrate_pages_sync mm/migrate.c:1989 [inline]
 migrate_pages+0xf02/0x1840 mm/migrate.c:2098
 do_mbind mm/mempolicy.c:1394 [inline]
 kernel_mbind mm/mempolicy.c:1537 [inline]
 __do_sys_mbind mm/mempolicy.c:1611 [inline]
 __se_sys_mbind+0xfd1/0x11c0 mm/mempolicy.c:1607
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1607
 x64_sys_call+0x2662/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:238
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000102077 -> 0x0000000000102071

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6418 Comm: syz.0.1339 Not tainted 6.14.0-rc1-syzkaller-00026-gd009de7d5428 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/04 19:29 upstream d009de7d5428 8f267cef .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mprotect_fixup / try_to_migrate_one
* Struck through repros no longer work on HEAD.